Substation system

ABSTRACT

To simplify the structure, realize autonomous automation, digitalize data, and effectively use data by utilizing a network. A measuring card for measuring voltage and current according to values detected by the state detector that detects voltage and current of the system, a protection card for performing a protective arithmetical operation according to values detected by the state detector and outputting a protection command to a controller, and a control card for performing a protective arithmetical operation according to values detected by the state detector and outputting a control command to a controller are integrated within an on-site cubicle, wherein the protection card, measuring card, and control card are connected to the substation monitoring and controlling device via a serial bus which is shared by those cards, and data is sent and received between those cards and the monitoring and controlling device via the serial bus.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a substation system and morespecifically to a substation system that applies information technology(IT) to apparatuses for protecting and controlling transformationequipment connected to the power system in order to reduce the size ofthe transformation equipment, enable autonomous automation, digitalizedata, and effectively use the data by utilizing a network.

[0003] 2. Prior Art

[0004] Among power systems, a power transmission system and a powerdistribution system are equipped with a substation that boosts ordeboosts outputs from a power generator or deboosts voltage of thesystem. In addition to a transformer that boosts or deboosts voltage,the substation has a device for collecting and distributing electricpower, a device or system for controlling power flow, and a device forprotecting and controlling devices located inside the substation.

[0005] For example, a circuit breaker used for a gas insulatingswitchgear (GIS) is equipped with a gas pressure sensor for detectinggas pressure, an acceleration sensor for detecting signals emitted inassociation with a problem, and a current and voltage detector; and atransformer is equipped with a thermometer, pressure gauge, oil-levelsensor, and current detector as sensors that detect the state of thetransformer.

[0006] These sensors are connected to a protection device, measuringdevice, control device, and device monitoring device via cables thattransmit electric signals. Furthermore, the protection device, measuringdevice, control device, and device monitoring device are connected to ahigher-rank substation monitoring and controlling device via individualcables that transmit electric signals.

[0007] The substation monitoring and controlling device monitors thestate of the circuit breaker and the transformer based on theinformation obtained by various sensors, displays the monitored resultson the screen, and outputs operation commands to the circuit breaker andthe like. That is, it monitors the state of the substation at a remotelocation and remotely operates the circuit breaker and the like.

[0008] In conventional technology, a plurality of devices arranged at alower-rank side are individually connected to the substation monitoringand controlling device via individual cables, thereby using severalcables, which complicates the structure. Further, a plurality oflower-rank side devices are connected to each sensor, which uses severalcables and even further complicates the structure.

[0009] Furthermore, protection, control, and monitor of devices at aremote location also complicate the structure of the substation system.Moreover, the use of analog signals prevents effective use of data.

SUMMARY OF THE INVENTION

[0010] The objective of the present invention is to provide a substationsystem that enables simplification of the structure and effective use ofdata.

[0011] To solve said problems, the present invention comprises a statedetector for detecting the state of monitored objects connected to apower system; a controller for controlling controlled objects connectedto said power system according to control information; amonitor-information creating device for exchanging information with saidstate detector using digital signals as media and also creatinginformation about the state of said monitored objects; and acontrol-information creating device for creating control information forcontrolling said controller, converting the created control informationalong with received control information into digital signals andtransmitting the signals to said controller, wherein saidmonitor-information creating device and said control-informationcreating device are connected to a monitoring and controlling device forcollecting information about the state of said monitored objects andoutputting control information for controlling said controlled objectsvia a signal transmission path shared by those devices, and exchangeinformation with said monitoring and controlling device using digitalsignals as media.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a schematic diagram showing a system according to anembodiment of the present invention.

[0013] FIG.2 illustrates an example in which state detectors areinstalled in a GIS.

[0014] FIG.3 illustrates an example in which state detectors areinstalled in a transformer.

DESCRIPTION OF THE INVENTION

[0015] An embodiment of the present invention will be described withreference to the drawings. FIG.1 is a schematic diagram of a system inaccordance with an embodiment of the present invention. In FIG.1, amongpower systems, a substation that is connected to a power transmissionsystem or a power distribution system is equipped with transformationequipment 10, such as a transformer, circuit breaker, and disconnector(not shown), which are monitored and controlled objects. An on-sitecubicle 12 is installed near the transformation equipment 10.

[0016] The transformation equipment 10 comprises a state detector 14 fordetecting the state of the monitored objects (circuit breaker,transformer, etc.), a controller 16 for controlling the controlledobjects (circuit breaker, etc.) according to control information, andanother state detector 18.

[0017] The state detector 14 is, for example, as shown in FIG.2,installed in a gas insulating switchgear (GIS) 17 and comprises awire-wound PCT (Potential Current Transformer) sensor for measuringvoltage and current of the system and an electro-optic converter forconverting electric signals detected by the PCT sensor into opticalsignals. The electro-optic converter is connected to an optical serialprocess bus 20.

[0018] The controller 16 is installed in the GIS 17 and comprises anopto-electric converter for converting optical signals sent from theoptical serial process bus 20 into electric signals and an actuator or atrip coil for controlling the GIS 17 according to a protection commandor an operation command that is output from the opto-electric converter.

[0019] The state detector 18 is installed in the GIS 17 shown in FIG.2or in a transformer 19 shown in FIG.3, and comprises, as devicemonitoring sensors for sensing the state of various devices, a gaspressure sensor 18 a for detecting gas pressure in the GIS 17, atemperature sensor 18 b for detecting temperature in the transformer 19,a pressure sensor 18 c for detecting nitrogen gas pressure in thetransformer 19, an oil-level sensor 18 d for detecting the oil level inthe transformer 19, a current sensor 18 e for detecting current in thetransformer 19, and also has an electro-optic converter for convertingelectric signals that are output from each sensor into optical signals.The electro-optic converter is connected to the optical serial processbus 22. Furthermore, the device monitoring sensors can include ahumidity sensor for detecting humidity by means of a switchgear (SWGR),a sonic sensor for detecting vibration, an insulation deteriorationsensor for detecting insulation deterioration, and an odor sensor fordetecting overheating of a device.

[0020] Within an on-site cubicle 12, Web server terminal cards 24 and26, a protection card 28, a measuring card 30, a control card 32, adevice monitoring card 34, and a mobile terminal card 36 are integratedwith optical serial process buses 20 and 22. Each Web server terminalcard 24 and 26 is connected to a time server 38, and also connected to asubstation monitoring and controlling device 42 via a serial bus 40.

[0021] The protection card 28 is structured as a protective device whichperforms an arithmetical operation based on the information sent fromthe state detector 14 in order to protect controlled objects and outputsa protection command as control information. The measuring card 30 isstructured as a measuring instrument which measures, for example,voltage and current of the system or voltage and current of the GIS 17based on the information sent from the state detector 14 to check thestate of the monitored objects, and outputs measurements to the Webserver terminal card 24. The control card 32 is structured as a controldevice which performs an arithmetical operation based on the informationsent from both the state detector 14 and the substation monitoring andcontrolling device 42 in order to control the controlled objects, andoutputs an operation command and a trip command to the controller 16 ascontrol information. The device monitoring card 34 is structured as adevice monitor which indicates the presence or absence of a problem inobjects being monitored based on the information sent from the statedetector 18 and outputs the results to the Web server terminal card 26.The mobile terminal card 36 is structured as a device which performs anarithmetical operation so as to exchange information with a mobileterminal.

[0022] That is, the measuring card 30 and the device monitoring card 34are structured as monitor-information creating devices which exchangeinformation with the state detectors 14 and 18 via optical serialprocess buses 20 and 22, respectively, (by using optical signals asmedia), and create information about the state of the objects beingmonitored. The protection card 28 and the control card 32 are structuredas control-information creating devices which create control informationfor controlling the controller 16, convert the created controlinformation along with control information received from the serial bus40 into optical signals, and transmit the signals to the controller 16.Those monitor-information creating devices and control-informationcreating devices are integrated within the on-site cubicle 12.

[0023] The Web server terminal cards 24 and 26 exchange information, forexample, based on HTML (Hypertext Markup Language), with the protectioncard 28, measuring card 30, control card 32, and device monitoring card34, transmit information from those cards as digital serial data to thesubstation monitoring and controlling device 42 via the serial bus 40,receive serial data from the substation monitoring and controllingdevice 42 via the serial bus 40, and distribute the received data toeach card.

[0024] Furthermore, the Web server terminal cards 24 and 26 receive timeinformation from a time server 38 and distribute the time information toeach card so that the time can be synchronized among the cards. That is,the time server 38 receives GPS (Global Positioning System) signals froma satellite 44 via an antenna 46 and transmits time informationcontained in the GPS signals to the Web server terminal cards 24 and 26.

[0025] The serial bus 40, which constitutes a signal transmission path,is structured as a substation in-house LAN (Local Area Network), andserial data transmitted via the serial bus 40 is created in accordancewith an international standard protocol (communication standards), forexample, a protocol IEC 61850 or 61375 specified by the InternationalElectrotechnical Commission (IEC). The protection card 28, measuringcard 30, control card 32, and device monitoring card 34 are connected tothe serial bus 40 via the Web server terminal circuits 24 and 26, andare also connected to the substation monitoring and controlling device42 via the single serial bus 40 shared by those cards.

[0026] The substation monitoring and controlling device 42 is equippedwith personal computers 48 and 50 to function as a device which collectsinformation about the state of the objects being monitored and outputscontrol information, for example, an operation command and a tripcommand to control the controlled objects. The personal computers 48 and50 are connected to the serial bus 40, and also connected, via aninterface 52, to the Internet 54 which is a communication network. Thescreen of each personal computers 48 and 50 displays images about thestate of each monitored object, and each personal computer 48 and 50outputs various operation commands as control information based on theoperation by an operator. It is possible to use an intranet or a publicline as a communication line instead of the Internet 54.

[0027] Both a maintenance managing device 56, which is a maintenancebase for an electric power company, and another maintenance managingdevice 58, which is a maintenance base for a manufacturing company thatmanufactures devices for the substation, are connected to the Internet54.

[0028] Operated by a maintenance engineer, the maintenance managingdevices 56 and 58 exchange information with the substation monitoringand controlling device 42 via the Internet 54, monitor the presence orabsence of a problem in objects being monitored based on the informationsent from the monitoring and controlling device 42, and carry out trendmanagement and history management of the monitored objects at a remotelocation. In this case, each maintenance managing device 56 and 58establishes a database to incorporate necessary data via the Internet54, and based on the data stored in the database, each maintenancemanaging device performs various analyses, diagnoses about the monitoredobjects and controlled objects, thereby confirming indications ofpotential problems or immediately taking countermeasures in case of anoccurrence of a problem. Moreover, by making a preventive maintenanceplan, managing inspection history, and performing parts management basedon the analytic results and diagnostic results, it is possible tosimultaneously increase both efficiency and reliability of maintenanceand operations.

[0029] According to this embodiment, the protection card 28, measuringcard 30, control card 32, and device monitoring card 34 can exchangeinformation with the substation monitoring and controlling device 42 viathe single serial bus 40 shared by those cards, thereby reducing thenumber of cables to one cable and simplifying the structure.

[0030] Furthermore, according to this embodiment, the protection card28, measuring card 30, control card 32, device monitoring card 34, andmobile terminal card 36 are connected to the state detectors 14 and 18and the controller 16 via optical serial process buses 20 and 22;therefore, the number of cables that connect those cards to the statedetectors 14 and 18 or the controller 16 can be reduced, whichsimplifies the structure.

[0031] Moreover, according to this embodiment, the protection card 28,measuring card 30, control card 32, device monitoring card 34, andmobile terminal card 36 are integrated within the on-site cubicle 12;consequently, the system can have high performance and its size can besmall.

[0032] Furthermore, according to this embodiment, serial datatransmitted via the serial bus 40 is in accordance with an internationalstandard protocol; therefore, connections between differentmanufacturers' products can be standardized.

[0033] Moreover, in this embodiment, a wire-wound PCT sensor has beendescribed which is used as a voltage and current measuring sensor;however, by using a non-iron-core Rogowski coil as a current measuringsensor and using a sensor that divides voltage by means of a pluralityof capacitors as a voltage measuring sensor, it is possible to reduce apower loss further than the wire wound PCT sensor and also reduce thesize of the system.

[0034] As described above, according to the present invention, bothmonitor-information creating devices and control-information creatingdevices are connected to the monitoring and controlling device via asignal transmission path which is shared by those devices. This makes itpossible to simplify the structure, realize autonomous automation,digitalize data, and effectively use data by utilizing a network.

What is claimed is:
 1. A substation system comprising a state detectorfor detecting the state of monitored objects connected to a powersystem; a controller for controlling controlled objects connected tosaid power system according to control information; amonitor-information creating device for exchanging information with saidstate detector using digital signals as media and also creatinginformation about the state of said monitored objects; and acontrol-information creating device for creating control information forcontrolling said controller, converting the created control informationalong with received control information into digital signals andtransmitting the signals to said controller, wherein saidmonitor-information creating device and said control-informationcreating device are connected to a monitoring and controlling device forcollecting information about the state of said monitored objects andoutputting control information for controlling said controlled objectsvia a signal transmission path shared by those devices, and exchangeinformation with said monitoring and controlling device using digitalsignals as media.
 2. A substation system according to claim 1, whereinsaid monitor-information creating device and said control-informationcreating device are integrated within a cubicle and installed near saidmonitored and controlled objects.
 3. A substation system according toclaim 1, wherein said state detector converts the state of saidmonitored objects into electric signals, converts the electric signalsinto digital signals, and outputs the signals; and said controllerconverts received digital signals into electric signals and outputs thesignals to said controller.
 4. A substation system according to claim 1,wherein optical communication is used as a communication medium for saiddigital signals.
 5. A substation system according to claim 1, whereinsaid signal transmission path transmits information in accordance withan international standard protocol.